Greasezilla FOG Separation Equipment for Wastewater Treatment Facilities

Greasezilla FOG Separation Process

Fats, oils, and grease (FOG) are common problems in wastewater collection systems and treatment plants. When fats, oils, and grease are improperly disposed of down drains or sewers, they can accumulate and create blockages in the sewer system, leading to backups and overflows.

A wastewater treatment facility accepts trucked-in waste with high levels of FOG.
A wastewater treatment facility accepting trucked-in waste with high levels of FOG.

Many wastewater treatment facilities are accepting trucked-in wastes with high levels of FOG as utilities strive to remove this material from typical wastewater to avoid clogging in the collection system, reduce maintenance and backups, avoid the increased oxygen demand of these wastes in the treatment systems, and to reuse the energy that is contained within this material beneficially.

Trucked-in waste includes septage and other high-strength wastes such as grease trap waste, sewage wet well cleaning waste, and waste from food processors.

However, FOG can also cause many problems at wastewater treatment plants, including:

  • Reduces the efficiency of treatment processes
  • Accumulates in pipes, pumps, and other equipment, leading to blockages, clogs, and equipment failure
  • Increases the oxygen demand in secondary treatment systems
  • Creates a scum layer in aeration tanks which reduces the oxygen transfer efficiency
  • Unpleasant odors
  • Affects the quality of WWTP effluent
  • Increases maintenance costs
  • Increased cost of treatment and disposal
  • Excessive foaming in aeration tanks and digesters

Despite the problems with FOG, these wastes offer significant benefits in terms of revenue from tipping fees and feedstock for anaerobic digesters that produce biogas, which can be beneficially used as fuel.

FOG can be difficult to remove from wastewater, however, many facilities are installing specialized FOG separating processes to generate valuable products such as biofuel, which can then be sold or used to create energy. By generating income from the sale of biofuel, wastewater treatment facilities can offset some of the costs associated with FOG management. By managing FOG effectively, wastewater treatment facilities can improve their operations, reduce the risk of environmental harm, and generate income.


GreasezillaSM is the leading provider of FOG Separation equipment. It is a turnkey standalone system that optimizes FOG separation while producing a high-quality brown grease advanced biofuel.

GreasezillaSM leaves nothing to be landfilled and has a total operating cost of 1 to 2 cents per gallon. The separation process produces a high-quality advanced biofuel making Greasezill the ideal front-end pretreatment system for FOG waste.

The GreasezillaSM unit runs on brown grease; about 5 percent of the brown grease produced in each batch is pumped back into the system and used as fuel.

The GreasezillaSM system is installed before the headworks of a wastewater treatment facility. A standard system includes dual 10,000-gallon, double-wall, insulated steel tanks. As one tank heats and separates inputs, the other is harvested, drained, and reloaded. GreasezillaSM is a batch process that does not require chemicals or polymers.

Greasezilla Process

GreasezillaSM separates grease trap waste into three distinct layers:

Brown Grease (Biofuel)

Brown grease is a byproduct of the food industry that contains a mixture of fats, oils, and solids. It is generated from the cleaning and maintenance equipment used to produce fried foods, such as grills and deep-fat fryers. Approximately 5 to 15 percent of the finished volume is brown grease or advanced biofuel (ABF). Five percent of the ABF is returned to fuel the Greasezilla℠, and the remaining 95 percent can be used for other heat requirements at the plant or as a salable fuel substitute.

Greasezilla Diagram
Diagram depicting how Greasezilla breaks down trap waste into three layers.

Yellow Grease (Batter)

Yellow grease (Batter) is typically generated from cooking oil processing and cleaning. It can contain a mixture of organic materials, such as fats, oils, and grease; as well as, water and solids. Yellow grease makes up 3 to 5 percent of the finished volume and is an excellent feedstock for anaerobic digesters. Removing the brown grease, and feeding the yellow grease to anaerobic digesters at a relatively uniform rate minimizes the potential for digester upsets while increasing biogas production.

Residual Water

80 to 85 percent of the finished volume is residual water which is discharged to the influent of the wastewater treatment facility.

GreasezillaSM eases the financial burden of ever-increasing operation and maintenance costs associated with FOG management and helps wastewater treatment facilities:

Greasezilla Logo
Learn more at
  • Improve their treatment results
  • Reduce O&M costs
  • Reduce the risk of environmental harm
  • It provides an opportunity to generate income
  • Contribute to the development of sustainable energy sources.

By Mike Gillespie, P.E., President at Envirep

For a complete list of our products, CLICK HERE to view our manufacturer’s line card.

Envirep/TLC is a leading manufacturer’s representative and service provider for municipal and industrial water and wastewater treatment and pumping systems. We represent manufacturers of quality products, serving Eastern Pennsylvania, Maryland, New Jersey, Delaware, Washington D.C., Northern Virginia, and part of West Virginia.

Envirep’s staff of application engineers and field service technicians have decades of experience in equipment selection, design, operation, and maintenance. We are committed to providing our customers with prompt and professional service. We assist consulting engineers and end-users with technical support, from new plant design and plant upgrades to equipment replacements and service. Our experienced team is here to recommend the right product, part, and service for your application.